At a hearing before the Senate Energy andNatural Resources Committee, Steven Chu said two key challengesfacing the United States are climate change and making the nationmore energy independent.”Climate change is a growing and pressingproblem. It is now clear that if we continue on our current path,we run the risk of dramatic disruptive changes to our climate inthe lifetimes of our children and our grandchildren. At the sametime, we face immediate threats to our economy, our nationalsecurity that stem from our dependence on oil,” he said.

Chu said the Obama administration wouldwork to reduce greenhouse gas emissions that contribute to globalwarming through a cap-and-trade system. As part of such a systempower plants, oil refineries and industrial facilities that havehigh emissions would pay more than those that invest intechnologies that curb emissions.

Chu, who currently serves as director ofthe Lawrence Berkeley National Laboratory in California, alsounderscored the importance of energy efficient technologies,biofuels and solar energy in reducing the U.S. dependence onforeign oil.

Some senators from states with oil and gasreserves urged Chu and the incoming Obama administration toencourage greater production of domestic resources.

Senator Lisa Murkowski is a Republicanfrom Alaska.

“I feel very strongly that we have toenhance our domestic oil and gas production,” she said.

Chu said domestic oil and gas productionwould be part of a comprehensive energy policy under the newadministration. But he said the United States has about four orfive percent of the world’s oil reserves, and that a moreefficient use of energy would be a bigger factor in helping thenation decrease its dependency on foreign oil.

That brought a terse response from SenatorMary Landrieu, a Democrat from Louisiana, a state with offshore oiland gas reserves.

“I would urge you to be careful about thecomment about four percent. It is true we have four percent of theknown reserves, but there is great evidence to suggest that thereare a lot of reserves that are unknown,” said Landrieu.

Landrieu didn’t cite any evidence.

Despite the occasional pointedquestioning, Chu is expected to be confirmed by the Senate as earlyas next week.

Chu, a former chairman of the physicsdepartment at Stanford University, shared the Nobel Prize forphysics in 1997 for discovering a way to cool and trap atoms byusing laser light.